Apparatus for detecting temperature of semiconductor elements for power conversion

Abstract

An apparatus for detecting temperatures of power-conversion semiconductor elements, which is applicable to a system including a plurality of power-conversion semiconductor elements and a plurality of temperature signal outputs for outputting temperature signals correlated to temperatures of the respective semiconductor elements. In the apparatus, the temperature signal outputted from at least one of the temperature signal outputs is input directly to a microcomputer without passing through at least one input-output interface. The temperature signals outputted from the other two or more temperature signal outputs are input to a plurality of input ports of the at least one input-output interface sequentially connected to an output of the interface. The microcomputer detects the temperatures of the respective semiconductor elements based on the temperature signals received from the output port of the at least one input-output interface and the temperature signal received directly from the at least one of the temperature signal outputs.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is based on and claims the benefit of priority from earlier Japanese Patent Applications No. 2013-255769 field Dec. 11, 2013 and No. 2014-220603 filed Oct. 29, 2014, the descriptions of which are incorporated herein by reference.BACKGROUND[0002]1. Technical Field[0003]The present invention relates to an apparatus for detecting temperatures of semiconductor elements for power conversion.[0004]2. Related Art[0005]Conventionally, a known power converter, as disclosed in Japanese Patent Application Laid-Open Publication No. 2008-206345, includes a plurality of switching elements, such as insulated gate bipolar transistors (IGBTs), is configured such that temperatures of some of the plurality of switching elements can be detected by temperature sensing elements. More specifically, in such a power converter, a prespecified one of the switching elements is assumed to be hottest among the switching elements during use. In such a p...

AI Technical Summary

Benefits of technology

[0012]In the above embodiment, the temperature signal outputs are provided for the respective power-conversion semiconductor elements. This allows the microcomputer to detect the temperature of each of the plurality of power-conversion semiconductor elements. Hence, even though a prespecified one of the switching elements is initially assumed to be hottest during use of the system, another switching element may actually be hottest among the switching elements during use due to aging or the like of the system. Even in such a case, the microcomputer is able to determine which semiconductor element is hottest among the plurality of switching elements. It is thus possible to prevent the semiconductor elements from overheating and prevent enlargement of a temperature range where use of the system is restricted.

[0013]In addition, in the above embodiment, the temperature signal outputted from at least one of the plurality of temperature signal outputs is input directly to the microcomputer without passing through the at least one input-output interface. Therefore, even if the at least one input-output interface fails, paths can be ensured between the microcomputer and the temperature signal outputs other than the at least one of the temperature signal outputs that is not connected to the at least one input-output interface. Even if the at least one input-output interface fails, this can achieve fail-safe, such as power saving, and can thus prevent substantial degradation of the reliability of the system.

[0014]In addition, in the above embodiment, signal transferring paths between the microcomputer and the other two or more temperature signal outputs can be established by using the input-output interface. The input-output interface is configured such that the number of output ports is less than the number of input ports. Therefore, the number of input ports of the microcomputer required to detect the temperatures of the respective power-conversion semiconductor elements can be reduced less than the total number of power-conversion semiconductor elements. This allows the apparatus to be downsized and costs of the apparatus to be reduced.

[0016]In the above other embodiment, the temperature signal outputs are provided for the plurality of power-conversion semiconductor elements, one for each power-conversion semiconductor element. The microcomputer has the plurality of input ports for respectively receiving the temperature signals from the respective temperature signal outputs. That is, in the microcomputer is configured such that the number of the temperature signal outputs is equal to the number of the input ports. Thus, the microcomputer is able to detect the temperatures of the respective whole power-conversion semiconductor elements. Even though a prespecified one of the switching elements is initially assumed to be hottest during use of the system, another switching element may actually be hottest among the switching elements during use due to aging or the like of the system. Even in such a case, the microcomputer is able to determine which semiconductor element is hottest among the plurality of switching elements. It is thus possible to prevent the semiconductor elements from overheating and prevent enlargement of a temperature range where use of the system is restricted.

Problems solved by technology

There is a disadvantage that, if the power converter is not configured to detect a temperature of such another switching element, all the switching elements couldn't be reliably protected from overheating based on the detected temperature of the prespecified one of the switching elements assumed at the time of designing to be hottest during use.

However, in such a configuration, there is a disadvantage that the overheat protecting process may be performed even though the actual temperatures of the switching elements have not yet reached the upper-limit temperature, and a temperature range where use of the switching elements is restricted may enlarge.

Power-conversion semiconductor elements, whether switching elements or not, may suffer from such disadvantages.

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